Attempts to workaround docker daemon sending garbled container output.

Seems that when the host is heavily loaded, docker will mix in control
chars, etc, to the output of a container.  We try to filter as much as
possible, but sadly it's not just control chars; printable chars can
sneak through.

clientside/tmcc/linux/docker/dockerclient.pm

 #!/usr/bin/perl
 #
-# Copyright (c) 2017 University of Utah and the Flux Group.
+# Copyright (c) 2017, 2018 University of Utah and the Flux Group.
 # 
 # {{{EMULAB-LICENSE
 # 
@@ -282,6 +282,7 @@ sub container_run($$$$;$$$) {
     }
     $args->{'Image'} = $image;
     $args->{'Cmd'} = $cmd;
+    $args->{'Tty'} = JSON::PP::false;
     my ($code,$content,$resp);
     ($code,$content) = $self->container_create($id,$args);
     if ($code) {

clientside/tmcc/linux/docker/libvnode_docker.pm

@@ -4128,6 +4128,12 @@ sub analyzeImage($$)
 	    if ($needunlock);
 	return $code;
     }
+    # Santize the output.  For whatever reason(s), under heavy load, it
+    # comes with non-printable chars occasionally, and with CRLF.  Odd.
+    #$buf =~ s/[^[:ascii:]]//g;
+    #$buf =~ s/\r\n//g;
+    $buf =~ s/[\000-\011\014\015-\037\176-\255]//g;
+
     TBDebugTimeStamp("analyze.sh output:\n$buf");
     open(FD,">/vms/contexts/analyze-$iid");
     print FD $buf;